OO friendly monad

oomonad.scala

//Tony's monad
trait Monad[F[_]] {
  def point[A](a: => A): F[A]
  def bind[A, B](f: A => F[B]): F[A] => F[B]
}

//a Scala and OO-friendly monad
trait ScalaMonad[A] {
  def flatMap[B](f: A => ScalaMonad[B]): ScalaMonad[B] // checkout the return value compared to the bind()
  def map[B](f: A => B): ScalaMonad[B]
}

class ScalaMonadAdapter[A, F[_], M <: Monad[F]](val container: F[A], val m: M) extends ScalaMonad[A] {
  def flatMap[B](f: A => ScalaMonad[B]): ScalaMonad[B] =
    new ScalaMonadAdapter[B, F, M](
      m.bind({ a: A => f(a).asInstanceOf[ScalaMonadAdapter[B, F, M]].container })(container), m)
  def map[B](f: A => B): ScalaMonad[B] =
    new ScalaMonadAdapter[B, F, M](
      m.bind({ a: A => f(a).asInstanceOf[ScalaMonadAdapter[B, F, M]].container })(container), m)
}

object Main {
  def test1(m: ScalaMonad[Int]) =
    for (i <- m) yield i
  def test2(s: ScalaMonad[ScalaMonad[Int]]) =
    for (m <- s; i <- m) yield i
}